Colour science in dentistry

Abstract

The past decade or so has witnessed a marked increase in consumer awareness in virtually every aspect of modern life. The concomitant rise in consumer expectations has extended, of course, to dentistry and, in particular, to the more aesthetic aspects of the discipline, namely shade matching and tooth whiteness. As a consequence, various instrumental methods of shade matching have been launched commercially in recent years; in addition, considerable, commercial research effort is currently being focused on instrumental methods of assessing tooth 'whitening'. Such interest in 'aesthetic dentistry' has, in turn, resulted in the author's laboratories having received myriad enquiries from dental researchers in relation to colour perception, colour theory and instrumental colour measurement. Despite the importance of colour in relation to dentistry and the current, very high level of research interest in the subject, remarkably few, if any, references have appeared that concern the application of colour theory to dentistry; furthermore, the colorimetric aspects of shade matching and tooth whitening have received virtually no discussion in relevant journals. The high level of interest in colour in dentistry coupled with the paucity of publications in this particular area, prompted the research work presented here. This paper concerns both dental shade matching and tooth whitening. The first part of the paper deals with the basics of colour perception, colour theory and instrumental colour measurement, in terms of three key elements, namely light source, object and observer. The fundamental aspects of light sources, how they interact with objects and the manner in which these interactions are interpreted through human colour vision are discussed. The principles of colorimetry are then considered and the functioning of instrumental colour measuring instruments are discussed. Subsequent papers will review the various approaches that have been used for shade matching, including methods that have been devised for visual shade matching and the various systems that use instrumental methods of shade matching. Research findings will be presented that identify the variables (eg lighting, shade guides) which can influence the accuracy of visual shade matching. The concept of instrumental shade matching will be explained in relation to the principles of colour perception, colour theory and instrumental colour measurement. Finally, the subject of tooth whitening will be discussed, from a colorimetric viewpoint.